Preparation of UV-resistant PET fibres by direct melt spinning with on-line addition

In order to solve the uniform dispersion of inorganic particles and dispersion characterization, a batch of UV-resistant fibres has been manufactured by direct melt spinning with on-line addition. By combining image analysis software with OM images, the dispersion of TiO2 has been quantitatively analyzed. The formula of mass fraction of inorganic particles in fibre is deduced on the basis of crystallinity, and the calculated value is found consistent with theoretical value. Additionally, the comparative study of direct spinning and chip spinning shows that the former presents better dispersion of inorganic particles and superior performance. The tenacity of fibres from melt-direct spinning increases by 13.87%， the CV value decreases by 75.19% and Heywood diameter of TiO2 particles decreases by 13.97%. According to national standard (GB/T 18830-2009), UPF values of the fabric are found much greater than the standard [UPF>40, T(UVA)<5%]

Study on superabsorbent polyacrylonitrile-based fibre

207-210<span style="font-size: 16.0pt;font-family:Fd1490491-Identity-H;mso-bidi-font-family:Fd1490491-Identity-H">Superabsorbent polymer fibres with maximum water absorbency were produced using acrylonitrile and methyl methacrylate as monomers, N-hydroxymethyl acrylamide as potential cross linking agent, dimethyl sulfoxide as solution and azo-bisisobutyronitrile as initiator. The copolymer solution <span style="font-size:16.0pt; font-family:Fd1739072-Identity-H;mso-hansi-font-family:Fd1490491-Identity-H; mso-bidi-font-family:Fd1739072-Identity-H">was <span style="font-size: 16.0pt;font-family:Fd1490491-Identity-H;mso-bidi-font-family:Fd1490491-Identity-H">then spun using dry-wet spinning method with water as coagulation bath. The fibres thus produced were heated to get crosslinking structure and their surfaces were hydrolyzed by alkaline solution. <span style="font-size: 16.0pt;font-family:Fd1490491-Identity-H;mso-bidi-font-family:Fd1490491-Identity-H">The influence of hydrolyzing conditions, such as temperature and concentrations of alkaline solution and N-hydroxymethyl acrylamide,on the fibre structure and properties was also studied using FTIR, DSC, DMA and SEM techniques. The changes in storage modulus, <span style="font-size:16.0pt;font-family:Fd1765337-Identity-H;mso-hansi-font-family: Fd1490491-Identity-H;mso-bidi-font-family:Fd1765337-Identity-H">T<span style="font-size:16.0pt;font-family:Fd1765337-Identity-H;mso-hansi-font-family: Fd1490491-Identity-H;mso-bidi-font-family:Fd1765337-Identity-H">g <span style="font-size:16.0pt;font-family:Fd1490491-Identity-H;mso-bidi-font-family: Fd1490491-Identity-H">and surface structures of fibres were also studied. The superabsorbent polymer of about 40g/g water absorbency was obtained using N-hydroxymethyl acrylamide concentration of equal to about 10wt%monomer, alkali concentration of about 15wt% and hydrolyzing time of about 5 min. </span

Microstructure and Performance of a Porous Polymer Membrane with a Copper Nano-Layer Using Vapor-Induced Phase Separation Combined with Magnetron Sputtering

Antibacterial metalized poly(vinylidene fluoride) (PVDF) porous membranes with a nano-layer were obtained via the method of vapor-induced phase separation combined with magnetron sputtering of copper. Magnetron sputtering has such advantages as high deposition rates, low substrate temperatures, and good adhesion of films on substrates. The influence brought by deposition time on the microstructure, hydrophobic property, copper distribution state, anti-biofouling, and permeation separation performance was investigated via atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) spectrometry, contact angle measurements, and capillary flow porometry, along with the porosity, water flux, protein solution flux, rejection rate, water flux recovery rate, and antibacterial property. The results showed that copper particles formed island-type deposits on the membrane surface and were embedded into cross-section pores near the surface owning to the interconnection of pores. Subsequently, the water flux and protein solution flux declined, but the rejection rate and water flux recovery rate increased. Meanwhile, Cu-coated PVDF membranes exhibited an excellent antibacterial ability

Studies on poly (vinyl chloride)/silica dioxide composite hollow fiber membrane

Poly (vinyl chloride)/silica dioxide composite hollow fiber membranes were prepared by using the method of immersion-precipitation process. The influences of stretching ratio on the formation of the interfacial microporous of poly (vinyl chloride)/silica dioxide composite hollow fiber membranes were specifically investigated by scanning electron microscope, dynamic mechanical analysis, and finite element method. Results show that with the stretching ratio increasing, numerous IFM appear on the surface of membranes. Finite element method actually reflects the dynamic change of microporous structure of poly (vinyl chloride)/silica dioxide composite hollow fiber membranes

Development Strategy of Hollow Fiber Membrane Technology and Industry in China

Hollow fiber membrane (HFM) technology is one of the common key technologies for solving major problems including water and energy crises and environment pollution. It is also crucial for achieving high-quality development characterized by energy conservation, clean production, and improvement in system efficiency and product quality. In this article, the strategic demand, development status, and development trend of the HFM technology and industry are analyzed; the major challenges and innovation focus in its subfields in China are discussed; and the development goals by 2025 and 2030 are clarified. Moreover, four key tasks were proposed in terms of hollow fiber ultrafiltration/microfiltration membrane, high-quality hydrophobic membrane, new membrane technology, and waste membrane recycling. Furthermore, measures and suggestions were proposed in terms of talent management, innovation investment, industry standards, and international cooperation, to provide a reference for the high-quality development of HFM technology and industry in China

Novel Ultrafine Fibrous Poly(tetrafluoroethylene) Hollow Fiber Membrane Fabricated by Electrospinning

Novel poly(tetrafluoroethylene) (PTFE) hollow fiber membranes were successfully fabricated by electrospinning, with ultrafine fibrous PTFE membranes as separation layers, while a porous glassfiber braided tube served as the supporting matrix. During this process, PTFE/poly(vinylalcohol) (PVA) ultrafine fibrous membranes were electrospun while covering the porous glassfiber braided tube; then, the nascent PTFE/PVA hollow fiber membrane was obtained. In the following sintering process, the spinning carrier PVA decomposed; meanwhile, the ultrafine fibrous PTFE membrane shrank inward so as to further integrate with the supporting matrix. Therefore, the ultrafine fibrous PTFE membranes had excellent interface bonding strength with the supporting matrix. Moreover, the obtained ultrafine fibrous PTFE hollow fiber membrane exhibited superior performances in terms of strong hydrophobicity (CA &gt; 140&deg;), high porosity (&gt;70%), and sharp pore size distribution. The comprehensive properties indicated that the ultrafine fibrous PTFE hollow fiber membranes could have potentially useful applications in membrane contactors (MC), especially membrane distillation (MD) in harsh water environments

Design of Robust FEP Porous Ultrafiltration Membranes by Electrospinning-Sintered Technology

Perfluoropolymer membranes are widely used because of their good environmental adaptability. Herein, the ultrafine fibrous FEP porous membranes were fabricated with electrospinning-sintered technology. The effects of PVA content and sintering temperature on the fabricated membranes’ morphologies and properties were investigated. The results indicate that a kind of dimensionally stable network structure was formed in the obtained ultrafine fibrous FEP porous membranes after sintering the nascent ultrafine fibrous FEP/PVA membranes. The optimal sintering conditions were obtained by comparing the membranes’ performance in terms of membrane morphology, hydrophobicity, mechanical strength, and porosity. When the sintering temperature was 300 °C for 10 min, the porosity, water contact angle, and liquid entry pressure of the membrane were 62.7%, 124.2° ± 2.1°, and 0.18 MPa, respectively. Moreover, the ultrafine fibrous FEP porous membrane at the optimal sintering conditions was tested in vacuum membrane distillation with a permeate flux of 15.1 L·m−2·h−1 and a salt rejection of 97.99%. Consequently, the ultrafine fibrous FEP porous membrane might be applied in the seawater desalination field

Membrane Fouling Mechanism of HTR-PVDF and HMR-PVDF Hollow Fiber Membranes in MBR System

Membrane fouling has attracted a lot of attention in the membrane separation field. Herein, we selected the homogeneous-reinforced polyvinylidene fluoride (HMR-PVDF) and heterogeneous-reinforced polyvinylidene fluoride (HTR-PVDF) hollow fiber membranes to investigate the fouling mechanism of membranes in membrane bioreactor (MBR) systems. The filtration models, membrane adsorption experiment, and membrane resistance distribution after a long or short time operation were assessed to compare their antifouling properties in order to verify the optimal membrane. The outer surface, shown by an SEM observation of the HMR-PVDF and HTR-PVDF membranes, was rough and smooth, respectively. Moreover, the HMR-PVDF membranes had a higher adsorption capacity than the HTR-PVDF membranes when an equilibrium state was almost 2.81 times that of the original membrane resistance. A cleaning method (mainly physical and chemical) was utilized to illustrate the operational stability of the membranes. In summary, the HMR-PVDF hollow fiber membrane presented better antifouling properties than the HTR-PVDF membranes, which was conducive to industrial implementation